Packet forwarding method, apparatus, and system

Abstract

A packet forwarding method includes that a session management network element sends a path identifier to a first device, where the first device includes an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session, the PDU session corresponds to a first terminal, the path identifier indicates a first path from the access network element to the user plane network element, the first path includes a part or all of a second path, and the second path is a path corresponding to a PDU session pre-established by the session management network element for a second terminal. The session management network element further sends, to the first device, identification information of a destination address corresponding to the path identifier.

What is claimed is: 
     
         1 . A method implemented by a session management network element, wherein the method comprises:
 sending a first path identifier to a first device, wherein the first device comprises an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session, wherein the PDU session corresponds to a first terminal, wherein the first path identifier indicates a first path from the access network element to the user plane network element, wherein the first path comprises a part or all of a second path, wherein the first path identifier is based on a second path identifier of the second path, and wherein the second path corresponds to a pre-established PDU session for a second terminal; and   sending, to the first device, identification information of a destination address corresponding to the first path identifier, to enable the first device to incorporate, based on the destination address, the first path identifier in data of the first terminal to obtain incorporate data, and forward the incorporated data through a third path corresponding to the destination address.   
     
     
         2 . The method of  claim 1 , wherein the first path is a first general packet radio service tunnelling protocol user plane (GTP-U) path, and wherein the second path is a second GTP-U path. 
     
     
         3 . The method of  claim 1 , wherein the first path comprises an intermediate user plane network element. 
     
     
         4 . The method of  claim 3 , wherein the first path identifier comprises a third path identifier indicating a fourth path from the access network element to the intermediate user plane network element and a fourth path identifier indicating a fifth path from the intermediate user plane network element to the user plane network element. 
     
     
         5 . The method of  claim 1 , further comprising sending path information corresponding to the first path identifier, wherein the path information comprises first identification information of the access network element and second identification information of the user plane network element that correspond to the first path. 
     
     
         6 . The method of  claim 5 , wherein the path information further comprises first tunnel information of the user plane network element and/or second tunnel information of the access network element. 
     
     
         7 . A method implemented by a first device, wherein the method comprises:
 receiving a first path identifier from a session management network element, wherein the first device comprises an access network element corresponding to a protocol data unit (PDU) session and a user plane network element corresponding to the PDU session, wherein the PDU session corresponds to a first terminal, wherein the first path identifier indicates a first path from the access network element to the user plane network element, wherein the first path comprises a part or all of a second path, wherein the first path identifier is based on a second path identifier of the second path, and wherein the second path corresponds to a pre-established PDU session for a second terminal;   receiving, from the session management network element, identification information of a destination address corresponding to the first path identifier;   obtaining data of the first terminal, wherein the data comprises the destination address;   incorporating, based on the destination address, the first path identifier in the data to obtain incorporate data; and   forwarding the incorporated data through a third path corresponding to the destination address.   
     
     
         8 . The method of  claim 7 , wherein the first path is a first general packet radio service tunnelling protocol user plane (GTP-U) path, and wherein the second path is a second GTP-U path. 
     
     
         9 . The method of  claim 7 , wherein the first path comprises an intermediate user plane network element. 
     
     
         10 . The method of  claim 9 , wherein the first path identifier comprises a third path identifier indicating a fourth path from the access network element to the intermediate user plane network element and a fourth path identifier indicating a fifth path from the intermediate user plane network element to the user plane network element. 
     
     
         11 . The method of  claim 7 , further comprising receiving, from the session management network element, path information corresponding to the first path identifier, wherein the path information comprises first identification information of the access network element and second identification information of the user plane network element that correspond to the first path. 
     
     
         12 . The method of  claim 11 , wherein the path information comprises first tunnel information of the user plane network element and/or second tunnel information of the access network element. 
     
     
         13 . A communication apparatus, comprising:
 a memory configured to store instructions; and   a processor coupled to the memory and configured to:
 send a first path identifier to a first device, wherein the first device comprises an access network element corresponding to a protocol data unit (PDU) session or a user plane network element corresponding to the PDU session, wherein the PDU session corresponds to a first terminal, wherein the first path identifier indicates a first path from the access network element to the user plane network element, wherein the first path comprises a part or all of a second path, wherein the first path identifier is based on a second path identifier of the second path, and wherein the second path corresponds to a pre-established PDU session for a second terminal; and 
 send, to the first device, identification information of a destination address corresponding to the first path identifier, to enable the first device to incorporate, based on the destination address, the first path identifier in data of the first terminal to obtain incorporate data, and forward the incorporated data through a third path corresponding to the destination address. 
   
     
     
         14 . The communication apparatus of  claim 13 , wherein the first path is a first general packet radio service tunnelling protocol user plane (GTP-U) path, and wherein the second path is a second GTP-U path. 
     
     
         15 . The communication apparatus of  claim 13 , wherein the first path comprises an intermediate user plane network element. 
     
     
         16 . The communication apparatus of  claim 15 , wherein the first path identifier comprises a third path identifier and a fourth path identifier, wherein the third path identifier indicates a fourth path from the access network element to the intermediate user plane network element, and wherein the fourth path identifier indicates a fifth path from the intermediate user plane network element to the user plane network element. 
     
     
         17 . The communication apparatus of  claim 13 , wherein the processor is configured to send, to the first device, path information corresponding to the first path identifier, wherein the path information comprises first identification information of the access network element and second identification information of the user plane network element that correspond to the first path. 
     
     
         18 . The communication apparatus of  claim 17 , wherein the path information comprises first tunnel information of the user plane network element and/or second tunnel information of the access network element. 
     
     
         19 . A communication apparatus being an access network element corresponding to a protocol data unit (PDU) session; or a user plane network element corresponding to the PDU session, comprising:
 a memory configured to store instructions; and   a processor coupled to the memory and configured to:
 receive a first path identifier from a session management network element, wherein the PDU session corresponds to a first terminal, wherein the first path identifier indicates a first path from the access network element to the user plane network element, wherein the first path comprises a part or all of a second path, wherein the first path identifier is based on a second path identifier of the second path, and wherein the second path corresponds to a pre-established PDU session for a second terminal; 
 receive, from the session management network element, identification information of a destination address corresponding to the first path identifier; 
 obtain data of the first terminal, wherein the data comprises the destination address; 
 incorporate, based on the destination address, the first path identifier in the data to obtain incorporate data; and 
 forward the incorporated data through a third path corresponding to the destination address. 
   
     
     
         20 . The communication apparatus of  claim 19 , wherein the first path is a first general packet radio service tunnelling protocol user plane (GTP-U) path, and wherein the second path is a second (GTP-U) path.